I've never had any kind of a "stop", what I've always done was find some sort of visual reference, the current boat it's the gas cap being aligned with the rear crossbar of the lift cradle. Our place we commonly deal with low water in the fall so I usually run the bunks just low enough to allow the skegs to clear the rear crossbar but the prop stays behind that bar, that also usually centers the motor in the cradle. The response hull is super easy to set up bunks, the rear spacing just outside a set of chines and i think slightly narrower at the front, centers itself as you lift it. The trailer bunks are a good starting point.